Gas filling system and gas filling apparatus

ABSTRACT

A gas filling apparatus in the gas filling system includes a precooler for cooling hydrogen gas supplied from the gas supply source ( 11 ) and discharges the hydrogen gas cooled by the precooler to fill the hydrogen gas into the gas tank. The temperature of the hydrogen gas cooled by the precooler is detected by a gas temperature sensor that detects, upstream of the gas tank, a temperature of the hydrogen gas cooled by the precooler. A flow rate controller controls a filling flow rate of the hydrogen gas to be filled into the gas tank, based on the detected temperature of the hydrogen gas. For example, when the detected temperature of the hydrogen gas is high, the filling flow rate is reduced as compared to that when the detected temperature of the hydrogen gas is lower.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a gas filling system for filling gas via a gas filling apparatus installed in a hydrogen station, for example, into a gas tank mounted on a vehicle, for example.

2. Description of the Related Art

At the time of filling fuel gas, a gas-fueled vehicle, on which a gas tank is mounted, such as a fuel cell vehicle, pulls into a gas station and the gas tank is filled with the fuel gas from a filling nozzle of a gas filling apparatus. It is known that when the fuel gas is hydrogen gas, the temperature increases as the fuel gas is filled. A hydrogen gas filling apparatus described in Japanese Patent Application Publication No. 2005-83567 (JP-A-2005-83567) is provided with a cooling means (a so-called precooler) to precool the hydrogen gas by heat exchange with a coolant and the cooled hydrogen gas is filled into the gas tank, so that the time for filling up is reduced. In the hydrogen gas filling apparatus, in order to prevent the occurrence of condensation when the hydrogen gas is over-cooled, the supply pressure of the hydrogen gas is detected and the flow rate and the temperature of the coolant supplied to the cooling means is controlled based on the results of detection.

However, when a plurality of fuel cell vehicles are consecutively filled up, for example, there is a possibility that the flow rate etc. of the coolant supplied to the cooling means is not appropriately controlled and the temperature of the coolant in the cooling means exceeds a predetermined temperature. When as a result the hydrogen gas that has not been appropriately cooled is filled into the gas tank, there is a fear that the temperature in the gas tank increases and reaches the design temperature (85° C., for example) before the completion of filling up. On the other hand, when the filling is stopped because of the insufficient cooling, there is a fear of making the driver wait.

SUMMARY OF THE INVENTION

The invention provides a gas filling system and a gas filling apparatus capable of optimizing the filling of a gas tank with gas via a gas filling apparatus equipped with a cooling device.

A gas filling system according to the invention includes: a gas tank; a gas filling apparatus, including a cooling device for cooling gas supplied from a gas supply source, that discharges the gas cooled by the cooling device to fill the gas into the gas tank; a gas temperature sensor that detects, upstream of the gas tank, a temperature of the gas cooled by the cooling device; and a flow rate controller that controls a filling flow rate of the gas to be filled into the gas tank, based on the temperature of the gas detected by the gas temperature sensor.

A gas filling apparatus according to the invention includes a cooling device for cooling gas supplied from a gas supply source and discharges the gas cooled by the cooling device to fill the gas into the gas tank. The gas filling apparatus is characterized by further including: a gas temperature sensor that detects, upstream of the gas tank, a temperature of the gas cooled by the cooling device; and a flow rate controller that controls a filling flow rate of the gas to be filled into the gas tank, based on the temperature of the gas detected by the gas temperature sensor.

According to the invention, the filling flow rate is varied based on the temperature of the gas cooled by the cooling device, so that it is possible to perform optimum filling according to the cooling power of the cooling device. Thus, it is possible to fill a predetermined filling amount of gas (both in the case of the filling amount for a full tank and in the case of the filling amount for a specified filling level) into the gas tank in a minimum period of time while maintaining the inside of the gas tank stable.

The flow rate controller may control the filling flow rate so that the filling flow rate is reduced as the temperature of the gas increases. Thus, it is made possible to complete filling a predetermined filling amount of gas in a short period of time while preventing the temperature in the gas tank from reaching the design temperature when the temperature of the gas is high because of the consecutive filling, for example. On the other hand, when the temperature of the gas is low, it is possible to complete filling a predetermined amount of gas in a shorter period of time than in the case of a higher gas temperature.

The gas filling system may further include a gas tank sensor that acquires information concerning the inside of the gas tank and the flow rate controller may control the filling flow rate based also on the information acquired by the gas tank sensor. With this configuration, it is possible to perform filling according to the state in the gas tank that is the subject to be filled. In addition, because the information in the gas tank is acquired, it is possible to perform control of the filling flow rate with higher accuracy as compared to the case where such information is estimated.

The gas tank sensor may include at least one of a gas tank temperature sensor and a gas tank pressure sensor. With this configuration, when it is detected that the temperature in the gas tank is high, for example, it is possible to suppress further increase in the temperature in the gas tank by reducing the filling flow rate.

The gas filling system may include a plurality of the gas tanks, the gas tank sensor may acquire the information for each of the gas tanks, and the flow rate controller may control the filling flow rate based on the information on the gas tank, in which a temperature is the highest, or on the information on the gas tank, in which a pressure is the lowest, among pieces of the information acquired by the gas tank sensors. With this configuration, it is possible to complete filling a predetermined filling amount of gas in a short period of time while preventing the temperature of all the gas tanks from reaching the design temperature.

The gas temperature sensor may detect the temperature of the gas in the cooling device. With this configuration, it is possible to optimize the filling based on the temperature of the gas in the cooling device.

The gas temperature sensor may detect the temperature of the gas after being discharged from the gas filling apparatus into the gas tank. With this configuration, it becomes unnecessary to take account of the influence of the disturbance in the gas filling apparatus with regard to the detected value of the temperature of the gas that has been cooled. In other words, it is possible to detect the temperature of the gas immediately before being filled that most affects the state in the gas tank and therefore, it is possible to control the filling flow rate with high accuracy.

The gas filling system may further include a connection unit for connecting the gas tank and the gas filling apparatus at the time of filling and the gas temperature sensor may detect the temperature of the gas at the connection unit. With this configuration, similarly to the above case, it is possible to minimize the influence of the disturbance on the detected value of the temperature of the gas that has been cooled. In addition, it is possible to increase the applicability, that is, for example, it is possible to utilize the connection unit to install the gas temperature sensor.

The connection unit may include a receptacle on the gas tank side and a filling nozzle on the gas filling apparatus side that is connected to the receptacle, and the gas temperature sensor may detect the temperature of the gas at the filling nozzle or at the receptacle.

The gas filling system of the invention may further include a display device that displays an indication that the filling flow rate is being controlled based on the temperature of the gas detected by the gas temperature sensor or an indication that the filling flow rate has been controlled based on the temperature of the gas detected by the gas temperature sensor. In this case, the display device may be provided in the gas filling apparatus or in a mobile body, on which the gas tank is mounted. With this configuration, it is possible to visually confirm that optimum filling according to the cooling power of the cooling device is being performed or has been performed in the gas filling apparatus or in the mobile body.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and further objects, features and advantages of the invention will become apparent from the following description of example embodiments with reference to the accompanying drawings, wherein like numerals are used to represent like elements and wherein:

FIG. 1 is a schematic diagram of a gas filling system according to an embodiment;

FIG. 2 is a configuration diagram of the gas filling system according to the embodiment;

FIG. 3 is a flow chart showing a flow of a filling operation in the gas filling system according to the embodiment; and

FIG. 4 is a diagram showing an example of a filling flow rate map used in the filling operation according to the embodiment.

DETAILED DESCRIPTION OF EMBODIMENTS

A gas filling system according to an example embodiment of the invention will be described below with reference to the attached drawings. An example of the gas filling system will be herein described, in which hydrogen gas is filled, via a gas filling apparatus, into a gas tank of a fuel cell vehicle equipped with a fuel cell system. As generally known, the fuel cell system includes a fuel cell that generates electricity through electrochemical reaction between fuel gas (hydrogen gas, for example) and oxidant gas (air, for example).

As shown in FIG. 1, the gas filling system 1 includes the gas filling apparatus 2 that is provided in a hydrogen station, for example, and a vehicle 3 supplied with the hydrogen gas from the gas filling apparatus 2.

As shown in FIG. 2, the gas filling apparatus 2 has clustered cylinders (gas supply source) 11 that store hydrogen gas, a filling nozzle 12 that discharges hydrogen gas into an on-board gas tank 30, and a gas line 13 that connects the clustered cylinders 11 and the filling nozzle 12. The filling nozzle 12, which is a part also referred to as a filling coupling, is connected to a receptacle 32 of the vehicle 3 when the hydrogen gas is filled. The filling nozzle 12 and the receptacle 32 constitute a connection unit that connects the gas filling apparatus 2 and the gas tank 30.

The gas line 13 is provided with: a compressor 14 that pressurizes and discharges the hydrogen gas supplied from the clustered cylinders 11; an accumulator 15 that stores the hydrogen gas that has been pressurized to a predetermined pressure by the compressor 14; a flow rate control valve 16 that controls the flow rate of the hydrogen gas supplied from the accumulator 15; a flow meter 17 that measures the flow rate of the hydrogen gas; a precooler 18 that precools the hydrogen gas flowing through the gas line 13; and a temperature sensor T that detects the temperature of the hydrogen gas downstream of the precooler 18, in this order from the clustered cylinders 11 side. The gas filling apparatus 2 includes a communication device 21, a display device 22, an ambient temperature sensor 23, and a controller 24. Various devices are electrically connected to the controller 24. Although not illustrated, a cutoff valve that opens the gas line 13 during filling is provided in or downstream of the accumulator 15.

The flow rate control valve 16 is an electrically driven valve and includes a stepping motor, for example, as the driving power source. The degree of opening of the flow rate control valve 16 is changed by the stepping motor according to the command from the controller 24, so that the flow rate of the hydrogen gas is controlled. In this way, the filling flow rate, at which the hydrogen gas is filled into the gas tank 30, is controlled. The thus-controlled filling flow rate is measured by the flow meter 17 and the controller 24 receives the measurement result and feedback-controls the flow rate control valve 16 so as to achieve a desired filling flow rate. It is also possible to use another flow rate controller than the flow rate control valve 16.

The precooler 18 cools the hydrogen gas that is supplied from the accumulator 15 at approximately room temperature, to a predetermined low temperature (−20° C., for example) by heat exchange. The type of the heat exchange in the precooler 18 may be any of the indirect type, the intermediate medium type, and the regenerative type and one of the publicly known structures may be used. For example, the precooler 18 has a pipeline portion, through which the hydrogen gas flows, and in the precooler 18, the pipeline portion is housed in a container, in which coolant flows, so that heat is exchanged between the hydrogen gas and the coolant. In this case, the cooling temperature of the hydrogen gas may be controlled by controlling the amount and the temperature of the coolant supplied to the container. In this way, the temperature of the hydrogen gas cooled by the precooler 18 is detected by the temperature sensor T and the signal indicative of the detection result is supplied to the controller 24.

The communication device 21 has a communication interface for performing wireless communication, such as infrared data communication, for example. The display device 22 displays various pieces of information, such as information on the filling flow rate during filling, on a screen. The display device 22 may be equipped with an operation panel for selecting or specifying the desired filling amount on the display screen.

The controller 24 is made up of a microcomputer including a central processing unit (CPU), a read only memory (ROM), and a random access memory (RAM) therein. The CPU performs desired calculations according to the control program to perform various processes and control operations. The ROM stores the control program executed by the CPU and control data. The RAM is mainly used as various workspaces for performing control processes. The controller 24 is electrically connected to the clustered cylinders 11, the compressor 14, the accumulator 15, and the precooler 18, in addition to the communication device 21 etc. that are connected to the controller 24 via control lines expressed by chain lines in FIG. 2 and controls the whole of the gas filling apparatus 2. In addition, the controller 24 transmits the information obtainable in the gas filling apparatus 2 to the vehicle 3 via the communication device 21.

The vehicle 3 includes the gas tank 30 and the receptacle 32. The gas tank 30 is a fuel gas supply source for supplying fuel to the fuel cell. The gas tank 30 is a high-pressure tank capable of storing hydrogen gas at 35 MPa or 70 MPa, for example. The hydrogen gas in the gas tank 30 is supplied to the fuel cell via the supply pipeline (not shown). The supply of hydrogen gas to the gas tank 30 is performed by the gas filling apparatus 2 via the receptacle 32 and a filling pipeline 34. The filling pipeline 34 is provided with a check valve 36 for preventing the hydrogen gas from flowing backward, for example. A temperature sensor 40 and a pressure sensor 42 detect the temperature and the pressure, respectively, of the hydrogen gas in the gas tank 30 and are provided in the supply pipeline or the filling pipeline 34.

The vehicle 3 includes: a communication device 44 that transmits and receives various pieces of information to and from the communication device 21 of the gas filling apparatus 2; a controller 46 made up of a microcomputer similarly to the controller 24 of the gas filling apparatus 2; and a display device 48 that displays various pieces of information on a screen. The communication device 44 is compatible with the communication device 21 and the communication device 44 has a communication interface for performing wireless communication, such as infrared data communication, for example. The communication device 44 is incorporated into the receptacle 32 or is fixed in a lid box of the vehicle 3 so that it is possible to establish communication between the communication devices 44 and 21 in a state where the filling nozzle 12 is connected to the receptacle 32. The controller 46 receives the results of detection from various sensors including the temperature sensor 40 and the pressure sensor 42 and controls the vehicle 3. The controller 46 transmits the information obtainable in the vehicle 3 to the gas filling apparatus 2 via the communication device 44. The display device 48 can be used as part of the car navigation system, for example.

In the above-described gas filling system 1, when hydrogen gas is filled into the gas tank 30 of the vehicle 3, first, the filling nozzle 12 is connected to the receptacle 32. Then, the gas filling apparatus 2 is activated. Upon the activation, the hydrogen gas stored in the accumulator 15 is cooled by the precooler 18 and then, the hydrogen gas is discharged from the filling nozzle 12 to the gas tank 30, whereby the hydrogen gas is filled into the gas tank 30. The gas filling system 1 of the present embodiment controls the filling flow rate according to the temperature of the cooled hydrogen gas.

Next, with reference to the flow chart of FIG. 3, the control of the filling flow rate in the gas filling system 1 will be described.

First, the filling operator connects the filling nozzle 12 to the receptacle 32 and when the filling starting operation is performed, by which the discharge of hydrogen gas from the gas filling apparatus 2 into the gas tank 30 is allowed, filling is started (step S1). Thus, the hydrogen gas stored in the accumulator 15 is cooled in the precooler 18 and then discharged into the gas tank 30.

Immediately after starting filling, the tank pressure, the tank temperature, and the precooler temperature are read in. The tank pressure is the pressure of the hydrogen gas in the gas tank 30 and is detected by the pressure sensor 42. The tank temperature is the temperature of the hydrogen gas in the gas tank 30 and is detected by the temperature sensor 40. The signals indicative of the results of detection of the tank pressure and the tank temperature are supplied to the controller 46. The controller 46 transmits the detected values of the tank pressure and the tank temperature to the gas filling apparatus 2 with the use of the communication device 44. The controller 24 of the gas filling apparatus 2 thus obtains the tank pressure and the tank temperature immediately after starting filling. The precooler temperature is the temperature of the hydrogen gas in the precooler 18 and is detected by the temperature sensor T. The controller 24 that directly receives the signal indicative of the result of detection of the precooler temperature obtains the precooler temperature immediately after starting filling.

After receiving these three pieces of information, the controller 24 determines the filling flow rate based on a filling flow rate map stored in the ROM or the like (step S2). The filling flow rate map Ma, examples of which are shown in FIG. 4, is a map, in which the vertical axis indicates the tank pressure and the horizontal axis indicates the tank temperature. The filling flow rate map Ma is set for each of a plurality of precooler temperatures (T₁, T₂, T₃, which satisfy the relation, T₁<T₂<T₃, for example). When the detected precooler temperature is T₁, the tank pressure is 40 MPa, and the tank temperature is 0° C., for example, the controller 24 selects D4 (m³/min) as the filling flow rate, for example.

The filling flow rate in the filling flow rate map Ma is a flow rate that enables the hydrogen gas to be filled into the gas tank 30 smoothly at a high speed under given conditions of the tank pressure, the tank temperature, and the precooler temperature. More specifically, each of the filling flow rates in the filling flow rate map Ma is the flow rate that enables a maximum amount of hydrogen gas (the filling amount for a full tank, for example) to be filled in a minimum period of time while the temperature in the gas tank 30 is prevented from reaching a predetermined upper limit value (85° C., for example). In the filling flow rate map Ma, the tank pressure is set at intervals of 10 MPa and the tank temperature is set at intervals of 10° C. However, these intervals may be arbitrarily set. Also the precooler temperature may be arbitrarily set at intervals of 2 to 3° C., 5° C., or 10° C., for example.

Two points concerning the order of the values of the filling flow rate in the filling flow rate map Ma will now be described. First, when the conditions of the tank pressure and the tank temperature are the same, the higher the precooler temperature is, the lower the value of the filling flow rate is. When the tank pressure is 40 MPa and the tank temperature is 0° C., for example, the filling flow rate at the precooler temperature T₂ is lower than the filling flow rate D4 at the precooler temperature T₁. When such a reduced filling flow rate is used, it is possible to complete filling in a minimum period of time while the temperature in the gas tank 30 is prevented from reaching an upper limit value even when the precooler temperature is increasing because of the consecutive filling.

Second, when the precooler temperature is the same, the filling flow rate may be increased as the tank pressure increases. In this case, the filling flow rate may be increased as the tank temperature decreases. For example, when the precooler temperature is T₁, among the filling flow rates A1 to H8 in the filling flow rate map Ma, the filling flow rate H1 (tank pressure: 80 MPa and tank temperature: −30° C.) is the highest and the filling flow rate A8 (tank pressure: 10 MPa and tank temperature: 40° C.) is the lowest. When a reduced filling flow rate is used in the case of a low tank pressure or a high tank temperature in this way, it is possible to complete filling in a minimum period of time while the temperature in the gas tank 30 is prevented from reaching an upper limit value.

In step S3, the controller 24 controls the gas filling apparatus 2 so that the filling flow rate is brought to the value that is determined in step S2. Specifically, while monitoring the result of measurement by the flow meter 17, the controller 24 controls the degree of opening of the flow rate control valve 16 so that the filling flow rate is brought to the determined value. In this way, hydrogen gas is filled into the gas tank 30 at a filling flow rate according to the given conditions of the tank pressure, the tank temperature, and the precooler temperature.

During the filling, at least one of the display device 22 of the gas filling apparatus 2 and the display device 48 of the vehicle 3 indicates that the filling is being performed at the filling flow rate determined in step S2. In other words, the filling operator can confirm that the filling flow rate is being controlled based on the conditions including the precooler temperature, by the indication on at least one of the display devices 22 and 48 of the gas filling system 1.

Thereafter, when a predetermined filling amount of gas (the amount of gas to be filled that is specified by the filling operator or the filling amount for a full tank) has been filled into the gas tank 30, the supply of hydrogen gas from the gas filling apparatus 2 is stopped and the filling is ended (step S4). Also after the completion of the filling or only after the completion of the filling, the indication similar to the above indication, that is, the indication that the filling flow rate has been controlled based on the conditions including the precooler temperature, for example, may be given on at least one of the display devices 22 and 48.

According to the gas filling system 1 according to this embodiment described above, it is possible to fill hydrogen gas into the gas tank 30 at a flow rate according to the tank pressure, the tank temperature, and the precooler temperature. In particular, although there is a case where the hydrogen gas temperature after cooling varies depending on the power of the precooler, according to this embodiment, it is possible to detect the precooler temperature and control the filling flow rate according to the detected precooler temperature. Thus, it is made possible to perform optimum filling according to the cooling power of the precooler 18 and it is therefore possible to fill a predetermined filling amount of gas into the gas tank 30 in a minimum period of time while maintaining the inside of the gas tank 30 stable.

As described above, for example, when control is performed so that the filling flow rate is reduced as the precooler temperature increases, it is possible to ensure a smooth, high-speed filling while the temperature of the inside of the gas tank 30 is prevented from exceeding an upper limit temperature. In other words, this effect can be said as follows: even when the cooling to a certain level is not performed by the precooler 18 yet, there is no need to interrupt or stop the filling operation and there is no need to make the filling operator or the driver wait. In addition, it is possible to fill up a plurality of vehicles 3 consecutively. On the other hand, when the precooler temperature is relatively low, by setting the filling flow rate relatively higher, it is possible to perform a smooth filling in a shorter period of time while the temperature of the inside of the gas tank 30 is prevented from exceeding an upper limit temperature.

In addition, because the information concerning the inside of the gas tank 30, that is, the tank pressure and the tank temperature, is actually acquired in order to determine the filling flow rate, it is possible to determine the more optimal filling flow rate as compared to the case where these values are estimated. In an alternative embodiment, control may be performed after determining the filling flow rate according to the precooler temperature without taking one of or both of the tank pressure and the tank temperature into consideration.

<Modifications>

Next, some modifications of the gas filling system 1 of the embodiment will be described. Each modification can be applied to the embodiment either alone or in combination with another modification.

In a first modification, the tank pressure and the tank temperature may be estimated when the filling flow rate is determined. In this case, the tank pressure and the tank temperature can be estimated with the use of the device(s) on the gas filling apparatus 2 side. For example, with regard to the tank pressure, a pressure sensor may be provided in the gas line 13 of the gas filling apparatus 2 and the tank pressure may be estimated based on the result of detection by the pressure sensor immediately after starting filling. On the other hand, the tank temperature may be estimated based on the result of detection by the ambient temperature sensor 23 immediately after starting filling. Such a method using the estimation is useful in the case where neither the gas filling apparatus 2 nor the vehicle 3 is provided with the communication means (the communication devices 21 and 44 described above).

In a second modification, the position of the temperature sensor T that detects the precooler temperature may be changed. In order to optimize the filing flow rate according to the temperature of the hydrogen gas after being cooled by passing through the precooler 18, it suffices that the temperature sensor T detects the temperature of the hydrogen gas between the precooler 18 and a point upstream the gas tank 30. Thus, the temperature sensor T may be provided in the receptacle 32 or the filling pipeline 34 on the vehicle 3 side. Alternatively, the temperature sensor T may detect the temperature of the hydrogen gas after being discharged from the gas filling apparatus 2 toward the gas tank 30. In another embodiment, the temperature sensor T may be provided in the filling nozzle 12 and may detect the temperature of the hydrogen gas at the filling nozzle 12.

When the detection by the temperature sensor T is performed at such a position, there is no need to consider the influence of the disturbance within the gas filling apparatus 2 on the detection value of the temperature of the cooled hydrogen gas. In other words, when the distance between the precooler 18 and the filling nozzle 12 is large, at the filling nozzle 12, the temperature of the hydrogen gas that has been cooled in the precooler 18 can exceed the temperature immediately downstream of the precooler 18 because of reception of heat in the piping of the gas line 13. However, when the hydrogen gas temperature is detected at a position downstream of the filling nozzle 12, such an influence can be avoided and it is possible to detect the temperature of the hydrogen gas immediately before being filled that influences the state of the inside of the gas tank 30 most. Thus, it is possible to control the filling flow rate more accurately.

In a third modification, the number of gas tanks 30 may be plural. When a plurality of gas tanks are mounted on the vehicle 3, the heat radiation varies depending on the mounting position and the amount of discharge from individual gas tanks varies depending on the manner in which the gas is supplied to the fuel cell. Thus, when there are a plurality of gas tanks 30, the filling flow rate may be determined from the filling flow rate map Ma based on the precooler temperature and the information (tank temperature and tank pressure) on the gas tank whose temperature is the highest or the gas tank whose pressure is the lowest among the plurality of gas tanks. In this way, it is possible to complete filling a predetermined filling amount of gas in a short period of time while preventing the temperature from reaching the upper limit temperature for every gas tank.

In the case of the third modification, the tank temperature and the tank pressure of each of the gas tanks may be acquired by providing each of the gas tanks with the temperature sensor 40 and the pressure sensor 42 or may be acquired with the use of one temperature sensor 40 and one pressure sensor 42 in total for all of the gas tanks. Alternatively, as described in connection with the second modification, the tank temperature and the tank pressure may be acquired by estimation for each of the gas tanks.

The gas filling system 1 according to the invention may be used not only in the case of hydrogen gas but also in the case of a gas whose temperature increases during filling. In addition, the gas filling system 1 can be applied not only to the vehicle 3, but also to a mobile body, such as an air plane, a ship, or a robot, on which a gas tank to be filled with gas supplied from the outside is mounted.

The invention has been described with reference to example embodiments for illustrative purposes only. It should be understood that the description is not intended to be exhaustive or to limit form of the invention and that the invention may be adapted for use in other systems and applications. The scope of the invention embraces various modifications and equivalent arrangements that may be conceived by one skilled in the art. 

1. A gas filling system comprising: a gas tank; a gas filling apparatus, including a cooling device for cooling gas supplied from a gas supply source, that discharges the gas cooled by the cooling device to fill the gas into the gas tank; a gas tank sensor that acquires information concerning the inside of the gas tank; a gas temperature sensor that detects, upstream of the gas tank, a temperature of the gas cooled by the cooling device; and a flow rate controller that controls a filling flow rate of the gas to be filled into the gas tank, based on the temperature of the gas detected by the gas temperature sensor and the information obtained by the gas tank sensor.
 2. The gas filling system according to claim 1, wherein the flow rate controller controls the filling flow rate so that the filling flow rate is reduced as the temperature of the gas increases.
 3. (canceled)
 4. The gas filling system according to claim 1, wherein the gas tank sensor includes at least one of a gas tank temperature sensor and a gas tank pressure sensor.
 5. The gas filling system according to claim 1, wherein: the gas filling system includes a plurality of the gas tanks; the gas tank sensor acquires the information for each of the gas tanks; and the flow rate controller controls the filling flow rate based on the information on the gas tank, in which a temperature is the highest, or on the information on the gas tank, in which a pressure is the lowest, among pieces of the information acquired by the gas tank sensors.
 6. The gas filling system according to claim 1, wherein the gas temperature sensor detects the temperature of the gas in the cooling device.
 7. The gas filling system according to claim 1, wherein the gas temperature sensor detects the temperature of the gas after being discharged from the gas filling apparatus to the gas tank.
 8. The gas filling system according to claim 1, further comprising a connection unit for connecting the gas tank and the gas filling apparatus at the time of filling, wherein the gas temperature sensor detects the temperature of the gas at the connection unit.
 9. The gas filling system according to claim 8, wherein: the connection unit includes a receptacle on the gas tank side and a filling nozzle on the gas filling apparatus side that is connected to the receptacle; and the gas temperature sensor detects the temperature of the gas at the filling nozzle.
 10. The gas filling system according to claim 8, wherein: the connection unit includes a receptacle on the gas tank side and a filling nozzle on the gas filling apparatus side that is connected to the receptacle; and the gas temperature sensor detects the temperature of the gas at the receptacle.
 11. The gas filling system according to claim 1, further comprising a display device that displays an indication that the filling flow rate is being controlled based on the temperature of the gas detected by the gas temperature sensor or an indication that the filling flow rate has been controlled based on the temperature of the gas detected by the gas temperature sensor.
 12. The gas filling system according to claim 11, wherein the display device is provided in the gas filling apparatus.
 13. The gas filling system according to claim 11, wherein the display device is provided in a mobile body, on which the gas tank is mounted.
 14. A gas filling apparatus, including a cooling device for cooling gas supplied from a gas supply source, that discharges the gas cooled by the cooling device to fill the gas into the gas tank, the gas filling apparatus comprising: a gas tank information acquisition portion that acquires information concerning the inside of the gas tank; a gas temperature sensor that detects, upstream of the gas tank, a temperature of the gas cooled by the cooling device; and a flow rate controller that controls a filling flow rate of the gas to be filled into the gas tank, based on the temperature of the gas detected by the gas temperature sensor and the information obtained by the gas tank information acquisition portion.
 15. A method for controlling filling of gas supplied from a gas supply source into a gas tank, comprising: detecting, upstream of the gas tank, a temperature of the gas cooled by a cooling device; acquiring information concerning the inside of the gas tank; and controlling a filling flow rate of the gas to be filled into the gas tank, based on the detected temperature of the gas and the information on the inside of the gas tank. 